Bridge



Nrrnn STATES' PATENT OFFICE.

WILLIAM P. TROWBRIDGE, OF XVA SHING'ION, DISTRICT OF COLUMBIA.

APPARATUS FOR DEEP-SEA SOUNDING AND METHOD OF CONVEYING AND PAYING- OUT LINE FOR OTHER PURPOSES.

Specification of Letters Patent No. 23,726, dated April 19, 1859.

To all whom 'it may concern.'

Be it known that I, WILLIAM P. 'IRow- BRIDGE, of VashingtOn, in the District of Columbia, have invented an Improvement in Apparatus for Deep-Sea Sounding; and I do hereby declare that the following is a full and exact description thereof, reference being had to the accompanying drawing and to the letters and figures marked thereon.

Figure I, view of the exterior of the case, the attached indicator and plummet; Fig. II, vertical section of the same; Fig. III, elevation of the indicator.

The letters refer to the same parts in all of the figures.

The apparatus herein described, is intended to be used for making deep-sea soundings with greater accuracy and in much less time. than it has been done by means of the instruments hertofore employed for this purpose.

In the methods of sounding now in use, the influence of what may be called the friction of the water upon the line is endwise resistanceand it was supposed that by using a plummet of thirty to forty pounds weight, and a very small line, this resistance would be so reduced that the retardation of the lead would not be sufcient to destroy conidence in the results. By careful investigation of the laws that govern the motion of the descending plummet, I find that the velocity, in the case of a thirty-two pound shot drawing a line of about one tenth of an inch in diameter, into and through the water is sixteen feetper second at the depth of fifty fathoms; at five hundred fathoms it is already reduced to four feet per second, and at the depth of three thousand fathoms the velocity is less than one foot per second; to pass below this depth with any confidence in the results is therefore quite impracticable. This difficulty in obtaining the depth does not arise from the distance to be measured, as it is in reality, small, or from the impenetrability of the fluid through which the lead has to pass, as water is nearly equally penetrable at all depths, but from the simple cause above stated viz, the endwise resistance to the line; to 'obviate this difficulty is the principal design and object of this invention, the depth of the water being determined by means of an apparatus in rapid iotion, entirely free from any retardation caused by the attached line.

I will first state the laws which govern the descent of the plummet inthe ocean when falling freely, that is, when not attached to the line, and then describe the apparatus, by means of which, this free motion is fully insured, while at the same time the line is carried to the bottom. I have found that the highest velocity is attained within twenty feet of the surface, and thatl this velocity is kept up, to the bottom without sensible change; that the rapidity of descent of the plummet depends in this case upon its weight and form alone. The highest velocities will therefore be attained by giving' to a leaden sinker, that form which offers the least resistance to motion. An ordinary deep-sea plummet will descend with a uniform velocity of twentyfive or thirty feet per second through all depths.

The distinctive feature of my apparatus consists in this, that the line is carried down in bulk in a cylindrical tube, to which the weight is attached one end being fixed at the surface the line is uncoiled from the descending sinker, while, in the mode heretofore employed, the coil remains in the vessel and the whole length of the line is dragged through the water.

The construction of the instrument shown in Figs. I and II is as follows: A tube A of tin or other metal contains the balls of line B, B, placed one above the other; it may be about four inches in dia-meter, its length being such as to carry the requisite length of line. a movable, conical cap C, which prevents the balls from escaping, having an aperture at the top through which the line D passes. The iron or leaden weight E has a hole through its entire length, and a shoulder F at the top which enters a corresponding recess I of a little larger diameter made at the bottom of the case or line holder A. Within this hole an iron bolt G, is placed, having a suitable specimen-box H, at the lower end, and a ring at the upper end, to which the end of the line leading from the outside of the lowest ball in the tube, is fastened, a few feet of the slack of the line being coiled around the shoulder F, which is thus made to ft snug in the recess I above At its Lipper end there is named. Then the instrument is used the end of the line D leading from the inside of the upper' ball, is held at the deck of the vessel, while, as the weight descends the line passes out, from each ball in succession, the outer end of every ball being secured to the inner end of the ball below it.

The length of line continued in the tube or case must be equal to, or greater than the depth of soundings, the surplus being given out as the line is hauled on deck after the plummet strikes the bottom. As the outside layer of the last, or lowest ball is paid out, the line then unwinds from the socket I, F, which liberates the plummet E and leaves it at the bottom, while the bolt Gr, and its contained specimen-box H are drawn up through the tube or case (which is also left at the bottom) and brought to the surface. I thus obviate entirely the endwise resistance to the line, as it remains stationary at that point of space in which the cylinder leaves it; the plummet is not retarded by the line, and it descends with a rapid and uniform velocity to the bottom; the paying out and all the circumstances of motion being uniform, great depths present no additional obstacle to the descent of the plummet.

In connection withl the mode herein described for conveying and discharging the line, various forms of apparatus may be used for the determination of the depth of the water. The instrument I have used for this purpose is known as Laxtons currentmeter represented in Fig. III, and in its position upon the top of the tube, in Fig. I, to which it is attached by a socket fitted loose so that the contact of the bolt Gr as it is drawn up, may detach it and bring it up for examination; the position of the index wheels M, which are turned by the revolving spiral vanes J, showing the depth in fathoms. The line may be coiled in balls as herein described, or in such other mode as will insure its rapid discharge from the case, it is of small size and its strength need not be greater than will suflice to bring up the meter and the bolt; the one I have used bears a direct strain of forty pounds, and a case or cylinder four inches in diameter contains about one mile of the line to each foot of its length.

My improvement is used for various purposes beside the measurement of depth as herein described among others maybe named the conveyance of a line from the shore to a stranded vessel, the case containing the line being attached to a rocket or other projectile; thus avoiding the resistance of the air to the motion of the line, which takes place when it is thrown by the modes heretofore used for this purpose.

I do not claim as a part of my invention the particular form of indicator referred to above as Laxtons current-meter. But as this is a better instrument for recording the distance passed over by the Iplummet in its descent than that known as Masseys indicator, which has been long in use, I have adopted it, and attached it in the mode described above, and shown in the drawings, for the pur-pose of registering the depth. A description of this current-meter may be found in the Magasin@ of Popi/,ZafrScz'c/nce, published in London in 1836.

The mode of conveying and discharging the line above described and hereinafterI claimed as my invention gives additional value and accuracy to the mode of ascertaining the depth by means of a revolving helix, inasmuch as I secure a rapid and uniform rate of descent through all depths no matter how great the depth may be; whereas in the present mode of sounding the velocity of descent,diminishes rapidly as the plummet descends. Moreover, by securing in the mode described a uniform and rapid rate of descent, the time of descent may be determined by employing an insulated wire for a soundino line or by combining a wire with the line in such a way as to determine the time when the weight strikes thc bottom by means o'f electricity as described in the hechanics Nlagazine for 1845. Then knowing the time and rate of descent the depth may be calculated with certainty. The risk of breaking the electric continuity is greatly diminished by my invention as the strain upon the line in the descent is very small in amount, while in the present mode the strain increases with the depth. These remarks are to explain the useful results of my invention, I do not claim any application of electricity to the apparatus.

What I claim is The mode of conveying and extending a line across or through a given space by means of a weight or projectile the line being compactly coiled within a tube or case which is attached to the weight or projectile and moves along with it, and is discharged from the case or holder as the weight or projectile advances, while one end of the line is retained at the starting point, substantially as herein described. I do not limit my claim to the particular manner of coiling` the line herein described, or to any one mode of giving motion to the same, which may be t-he force of gravity-the propelling power of a rocket or cannon, or other motive power.

W. P. TROWBRIDGE.

In presence of F. I. Murri-mr, JAS. F. TIMMs. 

